Idea 1) Put your dirty panties in your mouth, then go shopping. Bring a pad of paper and a pen, just in case you absolutely need to communicate with a complete stranger in your mute state.

Idea 2) Go to a pharmacy. Ask the help questions about adult diapers. Buy a pack. Walk to the car with it visible, then exchange it for a different size. And you know using them will be humbling as well.